tests/driver_mq3: don't use timex constant
tests/driver_mq3: don't use timex constant

using define constants from timex.h breaks build for some boards.

RIOT-OS/RIOT,beurdouche/RIOT,avmelnikoff/RIOT,gebart/RIOT,adjih/RIOT,gebart/RIOT,authmillenon/RIOT,kaleb-himes/RIOT,roberthartung/RIOT,syin2/RIOT,roberthartung/RIOT,jbeyerstedt/RIOT-OTA-update,lazytech-org/RIOT,avmelnikoff/RIOT,josephnoir/RIOT,yogo1212/RIOT,kaleb-himes/RIOT,adrianghc/RIOT,lazytech-org/RIOT,authmillenon/RIOT,LudwigKnuepfer/RIOT,immesys/RiSyn,ant9000/RIOT,toonst/RIOT,ant9000/RIOT,jasonatran/RIOT,LudwigKnuepfer/RIOT,basilfx/RIOT,rfuentess/RIOT,cladmi/RIOT,foss-for-synopsys-dwc-arc-processors/RIOT,dkm/RIOT,TobiasFredersdorf/RIOT,toonst/RIOT,BytesGalore/RIOT,syin2/RIOT,adjih/RIOT,gautric/RIOT,RIOT-OS/RIOT,x3ro/RIOT,mfrey/RIOT,plushvoxel/RIOT,TobiasFredersdorf/RIOT,kerneltask/RIOT,RIOT-OS/RIOT,yogo1212/RIOT,mfrey/RIOT,immesys/RiSyn,BytesGalore/RIOT,toonst/RIOT,OTAkeys/RIOT,jbeyerstedt/RIOT-OTA-update,kYc0o/RIOT,smlng/RIOT,basilfx/RIOT,avmelnikoff/RIOT,dailab/RIOT,RIOT-OS/RIOT,syin2/RIOT,adrianghc/RIOT,A-Paul/RIOT,Hyungsin/RIOT-OS,OTAkeys/RIOT,basilfx/RIOT,roberthartung/RIOT,kaspar030/RIOT,aeneby/RIOT,jfischer-phytec-iot/RIOT,lazytech-org/RIOT,jbeyerstedt/RIOT-OTA-update,smlng/RIOT,immesys/RiSyn,x3ro/RIOT,ant9000/RIOT,miri64/RIOT,foss-for-synopsys-dwc-arc-processors/RIOT,dailab/RIOT,neiljay/RIOT,gebart/RIOT,Ell-i/RIOT,mtausig/RIOT,miri64/RIOT,roberthartung/RIOT,josephnoir/RIOT,avmelnikoff/RIOT,biboc/RIOT,mfrey/RIOT,authmillenon/RIOT,Hyungsin/RIOT-OS,kaleb-himes/RIOT,LudwigOrtmann/RIOT,syin2/RIOT,gebart/RIOT,OlegHahm/RIOT,kbumsik/RIOT,Ell-i/RIOT,gautric/RIOT,lazytech-org/RIOT,hamilton-mote/RIOT-OS,TobiasFredersdorf/RIOT,aeneby/RIOT,OlegHahm/RIOT,aeneby/RIOT,ks156/RIOT,mfrey/RIOT,LudwigKnuepfer/RIOT,beurdouche/RIOT,kaleb-himes/RIOT,hamilton-mote/RIOT-OS,thomaseichinger/RIOT,adrianghc/RIOT,syin2/RIOT,Hyungsin/RIOT-OS,LudwigOrtmann/RIOT,hamilton-mote/RIOT-OS,kaspar030/RIOT,hamilton-mote/RIOT-OS,jasonatran/RIOT,neumodisch/RIOT,josephnoir/RIOT,OlegHahm/RIOT,OTAkeys/RIOT,mtausig/RIOT,josephnoir/RIOT,neumodisch/RIOT,gebart/RIOT,BytesGalore/RIOT,authmillenon/RIOT,mfrey/RIOT,dkm/RIOT,LudwigOrtmann/RIOT,dkm/RIOT,A-Paul/RIOT,BytesGalore/RIOT,Hyungsin/RIOT-OS,jasonatran/RIOT,x3ro/RIOT,beurdouche/RIOT,kaspar030/RIOT,yogo1212/RIOT,ant9000/RIOT,kYc0o/RIOT,jbeyerstedt/RIOT-OTA-update,jfischer-phytec-iot/RIOT,neumodisch/RIOT,jfischer-phytec-iot/RIOT,plushvoxel/RIOT,LudwigOrtmann/RIOT,kbumsik/RIOT,miri64/RIOT,beurdouche/RIOT,smlng/RIOT,foss-for-synopsys-dwc-arc-processors/RIOT,thomaseichinger/RIOT,adjih/RIOT,TobiasFredersdorf/RIOT,mtausig/RIOT,dailab/RIOT,yogo1212/RIOT,basilfx/RIOT,A-Paul/RIOT,OTAkeys/RIOT,A-Paul/RIOT,immesys/RiSyn,aeneby/RIOT,plushvoxel/RIOT,hamilton-mote/RIOT-OS,basilfx/RIOT,thomaseichinger/RIOT,toonst/RIOT,jfischer-phytec-iot/RIOT,kbumsik/RIOT,kerneltask/RIOT,Josar/RIOT,ks156/RIOT,kbumsik/RIOT,toonst/RIOT,lazytech-org/RIOT,jasonatran/RIOT,immesys/RiSyn,cladmi/RIOT,neiljay/RIOT,thomaseichinger/RIOT,roberthartung/RIOT,LudwigOrtmann/RIOT,adjih/RIOT,smlng/RIOT,aeneby/RIOT,neiljay/RIOT,biboc/RIOT,neumodisch/RIOT,avmelnikoff/RIOT,biboc/RIOT,rfuentess/RIOT,Josar/RIOT,plushvoxel/RIOT,adjih/RIOT,ks156/RIOT,biboc/RIOT,Ell-i/RIOT,neiljay/RIOT,smlng/RIOT,dailab/RIOT,kYc0o/RIOT,dkm/RIOT,mtausig/RIOT,gautric/RIOT,josephnoir/RIOT,x3ro/RIOT,jfischer-phytec-iot/RIOT,dkm/RIOT,cladmi/RIOT,jbeyerstedt/RIOT-OTA-update,neumodisch/RIOT,dailab/RIOT,Hyungsin/RIOT-OS,Josar/RIOT,RIOT-OS/RIOT,TobiasFredersdorf/RIOT,x3ro/RIOT,ks156/RIOT,neumodisch/RIOT,kbumsik/RIOT,yogo1212/RIOT,beurdouche/RIOT,Josar/RIOT,kerneltask/RIOT,kYc0o/RIOT,OTAkeys/RIOT,kaleb-himes/RIOT,miri64/RIOT,LudwigOrtmann/RIOT,biboc/RIOT,Josar/RIOT,LudwigKnuepfer/RIOT,ks156/RIOT,kaspar030/RIOT,Ell-i/RIOT,kerneltask/RIOT,Ell-i/RIOT,thomaseichinger/RIOT,LudwigKnuepfer/RIOT,adrianghc/RIOT,authmillenon/RIOT,kaspar030/RIOT,neiljay/RIOT,OlegHahm/RIOT,mtausig/RIOT,BytesGalore/RIOT,OlegHahm/RIOT,immesys/RiSyn,foss-for-synopsys-dwc-arc-processors/RIOT,kerneltask/RIOT,rfuentess/RIOT,gautric/RIOT,foss-for-synopsys-dwc-arc-processors/RIOT,gautric/RIOT,miri64/RIOT,rfuentess/RIOT,adrianghc/RIOT,yogo1212/RIOT,cladmi/RIOT,plushvoxel/RIOT,rfuentess/RIOT,jasonatran/RIOT,kYc0o/RIOT,cladmi/RIOT,authmillenon/RIOT,ant9000/RIOT,A-Paul/RIOT